The conventional wisdom is that a bridge declaration for game will have about a 50-50 chance of success if declarer has about 25 high card points, and the defense has 15. That's "all other things being equal."
But a 24 point declaration might well succeed if they are divided about equally between declarer and dummy, because of good "transportation," while a 26 point declaration divided 22 points and 4 might fail because of bad transportation.
Does a similar line of reasoning hold on defense? If one defender has made an opening bid or takeout double, the implication is that defender holds most of the defensive values, (and this fact is known to declarer). Is that a disadvantage? Or are there offsetting advantages, such as the information being made available to the other defender?